: The function of modern electrically powered prostheses is limited to actuation of 1 powered joint at a time such as a pincer (hand), elbow, or wrist. These are most often controlled by electrical signals or ElectroMyoGrams (EMGs) from a pair of skin surface electrodes. The joint being controlled is most commonly selected by tensing both muscles simultaneously which causes the controller to change function. EMG control signals are difficult to acquire from skin surface electrodes because of the intrinsic noise and stability problems of skin electrodes, and the limited active areas of small, closely spaced, and often atrophied muscles. For below-elbow amputees, simultaneous control of multiple powered joints (i.e. wrist, thumb, fingers) could be accomplished if multiple sources of high quality control signals were available. By implanting EMG telemeters to access all residual muscles, high quality control signals can be transmitted simultaneously from many muscles to a multi-functional, dexterous prosthesis. The Phase-1 project successfully demonstrated telemetry of low noise EMG signals from a chronically implanted rabbit using optical telemetry for power and signal. A Phase-2 project is proposed for clinical application and commercialization. First, the technology will be perfected and tested as a non-invasive device to establish a product for patients with certain types of sockets and to demonstrate the benefits of this technology. Telemeters will be embedded in roll-on silicone sleeves to eliminate the cumbersome snap-on wiring. For more traditional prosthesis suspensions, the telemeters will be adhered to the skin to eliminate electrical noise caused by movement of the prosthesis shell electrodes over the skin. Devices will be evaluated through steam sterilization cycles, in long term saline soak, long term animal implants, amputee laboratory evaluation tasks and home trials. The second goal, after the technology is proven reliable and functional in the non-invasive testing, we will be to implant devices in amputee volunteers who will benefit most from this approach. In addition to engineering measures and evaluations, simultaneous control of multiple actuators by a below elbow amputee will be demonstrated. During this time final regulatory approval will be sought and marketii begiaon a limited basis.